U.S. patent application number 10/439796 was filed with the patent office on 2003-11-20 for stereoscopic image display apparatus.
Invention is credited to Morishima, Hideki, Nishihara, Hiroshi, Sudo, Toshiyuki, Taniguchi, Naosato.
Application Number | 20030214497 10/439796 |
Document ID | / |
Family ID | 29422482 |
Filed Date | 2003-11-20 |
United States Patent
Application |
20030214497 |
Kind Code |
A1 |
Morishima, Hideki ; et
al. |
November 20, 2003 |
Stereoscopic image display apparatus
Abstract
The present invention discloses a stereoscopic image display
apparatus for which an image display unit can be freely selected,
and in which crosstalk is suppressed even if a transmissive image
display unit is used. The stereoscopic image display apparatus
according to the present invention includes an image display unit
in which pixel groups including pixels that display images
corresponding to observation positions respectively are arranged
cyclically; a lenticular array which substantially condenses light
rays from the respective pixels at the predetermined observation
positions and which is constituted by a plurality of horizontal
lens lines arranged vertically, each of which is formed by a
plurality of cylindrical lenses horizontally arranged at a
predetermined cycle. And the apparatus includes a limiting member
that limits light rays so that rays from a predetermined horizontal
pixel lines may reach only the horizontal lens line having the same
horizontal positions of cylindrical lenses.
Inventors: |
Morishima, Hideki; (Tochigi,
JP) ; Taniguchi, Naosato; (Saitama, JP) ;
Sudo, Toshiyuki; (Tochigi, JP) ; Nishihara,
Hiroshi; (Tokyo, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
345 PARK AVENUE
NEW YORK
NY
10154
US
|
Family ID: |
29422482 |
Appl. No.: |
10/439796 |
Filed: |
May 16, 2003 |
Current U.S.
Class: |
345/204 |
Current CPC
Class: |
G02B 30/27 20200101;
G02B 30/29 20200101 |
Class at
Publication: |
345/204 |
International
Class: |
G09G 005/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2002 |
JP |
2002-183627 |
May 9, 2003 |
JP |
2003-131709 |
Claims
What is claimed is:
1. A stereoscopic image display apparatus, comprising: an image
display unit in which a plurality of horizontal pixel lines is
provided in a vertical direction, and pixel groups including pixels
that display images corresponding to a plurality of observation
positions respectively are arranged cyclically; a lenticular array
which substantially condenses rays of light from the respective
pixels at the predetermined observation positions in a horizontal
plane, and which is constituted by a plurality of horizontal lens
lines arranged in the vertical direction, each of which is formed
by a plurality of cylindrical lenses arranged in the horizontal
direction at a predetermined cycle corresponding to each of the
pixel groups; and a limiting member that limits rays of light so
that rays of light from each of a predetermined horizontal pixel
line may reach the horizontal lens lines having the cylindrical
lenses whose horizontal positions are the same among the plurality
of horizontal lens lines, wherein rays of light from the pixels
that display images corresponding to the respective observation
positions reach predetermined observation positions through the
lenticular array and the limiting member.
2. A stereoscopic image display apparatus, comprising an image
display unit that is a transmissive image display unit in which a
plurality of horizontal pixel lines is provided vertically in a
vertical direction, and pixel groups including pixels that display
images corresponding to a plurality of observation positions
respectively are arranged cyclically; a light source being placed
in the back of the image display unit and illuminating the image
display unit; a lenticular array which substantially condenses rays
of light, passing through predetermined pixels in the image display
unit among rays of light from the light source, at the
predetermined observation positions in a horizontal plane, and
which is constituted by a plurality of horizontal lens lines
arranged in the vertical direction, each of which is formed by a
plurality of cylindrical lenses arranged in a horizontal direction
at a predetermined cycle corresponding to each of the pixel groups;
and a limiting member that limits rays of light from the light
source so that rays of light may pass through a predetermined
horizontal pixel line and reach the horizontal lens lines having
the cylindrical lenses whose horizontal positions are the same
among the plurality of horizontal lens lines, wherein rays of light
from the pixels that display images corresponding to the respective
observation positions reach predetermined observation positions
through the lenticular array and the limiting member.
3. The stereoscopic image display apparatus according to any one of
claims 1 and 2, wherein (in the image display unit) the pixel
groups are formed by horizontally arranging the pixels displaying
the images corresponding to the plurality of observation positions
respectively, each of the horizontal pixel lines includes the
plurality of horizontal pixel groups and a plurality of the
horizontal pixel lines is provided in the vertical direction so
that the pixel groups are shifted horizontally among the pixel
lines; and wherein each of the cylindrical lenses corresponds to
each of the pixel groups in the lenticular array.
4. The stereoscopic image display apparatus according to any one of
claims 1 and 2, wherein each of the pixel groups is formed in a
q.multidot.p matrix-like group by horizontally arranging q pixels
and vertically arranging p pixels, the pixels in each pixel groups
display images corresponding to the plurality of observation
positions respectively, and furthermore, the pixel groups are
arranged in the horizontal and vertical direction in a matrix-like
pattern; and wherein p cylindrical lenses are provided so as to
correspond to each of the pixel groups in the vertical direction in
the lenticular array.
5. The stereoscopic image display apparatus according to claim 3,
wherein the image display unit has c types of pixels that emerge c
colors of light fluxes that are different mutually, and are
arranged horizontally, and a number of the observation positions is
not an integral multiple of the c.
6. The stereoscopic image display apparatus according to claim 4,
wherein the image display unit has c types of pixels that emerge
rays of c colors that are different mutually, and are arranged in
the horizontal direction, and the number q of the pixels in the
horizontal direction is not an integral multiple of the c.
7. The stereoscopic image display apparatus according to any one of
claims 1 and 2, wherein the limiting member is an optical member in
which a plurality of cylindrical lenses provided so as to have an
optical power in the vertical direction and are arranged in the
vertical direction.
8. A stereoscopic image display system, comprising: the
stereoscopic image display apparatus according to any one of claims
1 and 2; and an image information supplying apparatus that supplies
image information, displayed in the image display unit, to the
stereoscopic image display apparatus.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a stereoscopic image
display apparatus, and in particular, to a stereoscopic image
display apparatus suitable for performing stereoscopic display in a
TV set, a VCR, a computer monitor, a game machine, and the
like.
[0003] 2. Description of Related Art
[0004] As a stereoscopic image display apparatus, there is, for
example, a so-called multiple lens system proposed in the published
European Patent Application No. 1 248 473 (A1).
[0005] This stereoscopic image display apparatus expresses
stereoscopic effects by displaying original images of a certain
observation object, corresponding to different observation
positions, on an image display unit, and leading light from the
image display unit so as to be able to observe these original
images from the observation positions (viewpoints)
respectively.
[0006] Nevertheless, this conventional stereoscopic image display
apparatus has the following defects to be improved. (1) Since it is
necessary to use a transmissive display as an image display unit
that displays the original images, degrees of freedom of display
unit selection are lowered.
[0007] In addition, though LCDs are widely used now as transmissive
display units, recent LCDs tend to largely scatter illumination
light when the illumination light penetrates each of the LCDs
because pixel structure is made fine so as to improve a viewing
angle characteristic. Therefore, so as to use such an LCD for a
multiviewpoint stereoscopic image display apparatus, it is
necessary to specify a direction of display light so that the
display light may reach only the observation positions,
corresponding to the respective pixels, in a location where the
display light from respective pixels is apart by desired
observation distance.
[0008] At this point, the above-described conventional stereoscopic
image display apparatus has the structure that gives directionality
to the illumination light that illuminates pixels of the
transmissive display unit. Nevertheless, there is a problem that,
when the diffusion of the LCD increases, there arises a problem
that, since the LCD scatters the illumination light even if the
directionality is given to the illumination light, arrival
positions of the illumination light in the observation plane shift,
and hence, a stereoscopic image cannot be properly observed because
so-called crosstalk arises.
[0009] (2) In the structure of the conventional stereoscopic image
display apparatus, when performing color display, there is no
position where it is possible to observe an image in colors since
colors are separated on an observation plane by the color filter
arrangement of the LCD.
[0010] (3) Moreover, in the stereoscopic image display apparatus
proposed in the above-described publication, since components,
proceeding in directions other than an observation position, in the
illumination light from a pixel are interrupted by using a mask, a
light efficiency is low.
SUMMARY OF THE INVENTION
[0011] The present invention aims to provide a stereoscopic image
display apparatus for which an image display unit can be freely
selected in which crosstalk does not arise even if a transmissive
image display unit with strong scattering is used, and whose light
efficiency is also high.
[0012] Moreover, the present invention also aims to provide a
multiviewpoint stereoscopic image display apparatus to be able to
suppress color separation when color display is performed.
[0013] To achieve the above-described objects, the stereoscopic
image display apparatus according to the present invention includes
an image display unit in which a plurality of horizontal pixel
lines is provided a vertical direction, and pixel groups including
pixels that display images corresponding to a plurality of
observation positions respectively are arranged cyclically; a
lenticular array which substantially condenses rays of light from
the respective pixels at the predetermined observation positions in
a horizontal plane, and which is constituted by a plurality of
horizontal lens lines which are arranged in the vertical direction,
each of the horizontal lens lines is formed by a plurality of
cylindrical lenses arranged in the horizontal direction at a
predetermined cycle corresponding to each of the pixel groups. And
the apparatus includes a limiting member that limits rays of light
so that rays of light from a predetermined horizontal pixel line
may reach only the horizontal lens lines having the cylindrical
lenses whose horizontal positions are the same among the plurality
of horizontal lens lines. Rays of light from the pixels that
display images corresponding to the respective observation
positions reach predetermined observation positions through the
lenticular array and the limiting member.
[0014] Features of the stereoscopic image display apparatus
according to the present invention will become clear by the
following description of specific embodiments with referring to
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a perspective view showing the structure of a
stereoscopic image display apparatus that is Embodiment 1 of the
present invention.
[0016] FIG. 2 is a diagram for explaining the distribution of
pixels in a display unit of the stereoscopic image display
apparatus to each viewpoint.
[0017] FIG. 3 is a perspective view showing a shift lenticular
array in the stereoscopic image display apparatus.
[0018] FIG. 4 is an explanatory diagram of image display light in
the stereoscopic image display apparatus.
[0019] FIG. 5 is a horizontal section of the stereoscopic image
display apparatus.
[0020] FIG. 6 is a horizontal section of the stereoscopic image
display apparatus.
[0021] FIG. 7 is a horizontal section of the stereoscopic image
display apparatus.
[0022] FIG. 8 is a horizontal section of the stereoscopic image
display apparatus.
[0023] FIG. 9 is a vertical section of the stereoscopic image
display apparatus.
[0024] FIGS. 10(A) and 10(B) are front views showing distribution
methods of subpixels of a color display unit in a stereoscopic
image display apparatus, which is Embodiment 2 of the present
invention, to respective viewpoints.
[0025] FIG. 11 is a front view showing a distribution method of
subpixels of a color display unit in a stereoscopic image display
apparatus, which is Embodiment 3 of the present invention, to
respective viewpoints.
[0026] FIG. 12 is a drawing showing a cylindrical lens arrangement
pattern of a shift lenticular array in Embodiment 3.
[0027] FIG. 13 is a front view showing a distribution method of
pixels of a display unit in a stereoscopic image display apparatus,
which is Embodiment 4 of the present invention, to respective
viewpoints.
[0028] FIG. 14 is a horizontal section of the stereoscopic image
display apparatus according to the Embodiment 4.
[0029] FIG. 15 is a horizontal section of the stereoscopic image
display apparatus according to Embodiment 4.
[0030] FIG. 16 is a horizontal section of the stereoscopic image
display apparatus according to Embodiment 4.
[0031] FIG. 17 is a horizontal section of the stereoscopic image
display apparatus according to Embodiment 4.
[0032] FIG. 18 is a drawing showing a shift lenticular array
pattern in the stereoscopic image display apparatus according to
Embodiment 4.
[0033] FIG. 19 is a perspective view showing the structure of a
stereoscopic image display apparatus that is Embodiment 5 of the
present invention.
[0034] FIGS. 20(A) and 20(B) are drawings for explaining the
relation between the shift lenticular array in Embodiment 1 and a
diagonal lenticular array sheet in Embodiment 5.
[0035] FIG. 21 is a drawing for explaining a production method of
molding the diagonal lenticular array sheet.
[0036] FIG. 22 is a perspective view showing the structure of a
stereoscopic image display apparatus that is Embodiment 6 of the
present invention.
[0037] FIG. 23 is a diagram for explaining the distribution of
pixels in a display unit of the stereoscopic image display
apparatus according to Embodiment 6.
[0038] FIG. 24 is a vertical section of the stereoscopic image
display apparatus according to embodiment 6.
[0039] FIG. 25 is a perspective view showing the structure of a
stereoscopic image display apparatus that is Embodiment 7 of the
present invention.
[0040] FIG. 26 is a vertical section of the stereoscopic image
display apparatus according to Embodiment 7.
[0041] FIG. 27 is a diagram for explaining the distribution of
pixels in a display unit of the stereoscopic image display
apparatus according to Embodiment 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0042] (Embodiment 1)
[0043] FIG. 1 shows the structure of a stereoscopic image display
apparatus that is Embodiment 1 of the present invention. In the
stereoscopic image display apparatus of this embodiment, the number
of observation positions (hereafter, these are called viewpoints)
is r, and the resolution is not biased in any direction, by
arranging pixels in a matrix (r=p rows.times.q columns) on a
display unit and distributing pixels, displaying respective
viewpoint images, vertically and horizontally.
[0044] The stereoscopic image display apparatus in this embodiment
has nine viewpoints composed of p=3, q=3, and r=9. This
stereoscopic image display apparatus comprises a display unit
(image display unit) 1, a horizontal lenticular lens 2 arranged in
the front side (side of an observation area 4) of the display unit
1, and a shift lenticular array 3 arranged in the front side of the
horizontal lenticular lens 2.
[0045] A transmissive image display device is used as the display
unit 1 in this embodiment, but other type image display device can
be freely selected without limiting thereto. For example, a
reflective or self-light-emitting display device can be also
used.
[0046] Respective viewpoints E1 to E9 in the observation area 4,
line up from the right to the left in this order. Each viewpoint is
not just a point but is an area having a certain horizontal
width.
[0047] FIG. 2 shows how original images corresponding to the nine
viewpoints (hereafter, these are called viewpoint images) are
displayed in respective pixels of the display unit 1. Reference
symbols D1 to D9 assigned to respective pixels shown by rectangular
frames in the drawing show respective viewpoint images, that
correspond to viewpoints E1 to E9. For example, a pixel D1 displays
a viewpoint image corresponding to the viewpoint E1, and a pixel D2
displays a viewpoint image corresponding to the viewpoint E2
respectively.
[0048] Here, image information to display respective viewpoint
images in the display unit 1 is supplied from an image information
supplying apparatus 20 such as a personal computer, a VCR, and a
DVD drive to a display unit drive circuit 21 of the stereoscopic
image display apparatus. The display unit drive circuit 21 drives
the display unit 1 on the basis of the inputted image information,
and nine viewpoint images are synthetically displayed in the
display unit 1 by pixels different from each other.
[0049] In FIG. 2, a pixel arrangement method in the display unit 1
is to repeatedly arrange pixels from D1 to D9 corresponding to nine
(=r) viewpoints in each horizontal line of pixels cyclically, and
to make the arrangement order (order of denoting which pixel
displays which viewpoint image) of pixels shifted by three (=q)
pixels every pixel line in the horizontal direction. In this case,
pixel arrangement order becomes the same every three (=p)
horizontal pixel lines.
[0050] A shift lenticular array 3 is constituted by arranging
cylindrical lens portions, each of which has an optical power in
the horizontal direction but does not have an optical power in the
vertical direction, horizontally and vertically in a predetermined
pattern.
[0051] In addition, in FIG. 1, the shift lenticular array 3 is
shown with being considerably expanded than actual size to make its
shape easily understood. Furthermore, in other drawings, the size
and positional relation to the shift lenticular array 3 and display
unit 1 (pixels) are made to differ from actual ones so as to make
optical actions etc. comprehensible. This is the same also about
the horizontal lenticular lens 2 explained later in detail.
[0052] By using FIG. 3, it will be explained how cylindrical lens
portions 3a constituting the shift lenticular array 3 are
arranged.
[0053] Though this will be explained later in detail, each
horizontal line (hereafter, this is called a horizontal lens line)
of the cylindrical lens portions 3a in the shift lenticular array 3
is provided in correspondence to each of the horizontal pixel lines
of the display unit 1. Moreover, each of the cylindrical lens
portions 3a constituting each horizontal lens line is provided in
correspondence to predetermined consecutive pixels (pixel group) of
a corresponding horizontal pixel line in the display unit 1.
[0054] In this embodiment, each of the cylindrical lens portions 3a
has horizontal width corresponding to horizontal width of nine (=r)
pixels (pixel group), and this shift lenticular array 3 is
constituted by arranging these cylindrical lens portions 3a
horizontally and vertically in a predetermined pattern.
[0055] In addition, each of the cylindrical lens portions 3a
constituting the shift lenticular array 3 has an optical power in
the horizontal direction, and does not have an optical power in the
vertical direction. Then, the horizontal optical power converts
divergent rays of light emerged from one point of the display unit
1 into a parallel rays of light, and a horizontal curvature of each
cylindrical lens portion 3a is set so as to give such a horizontal
optical power.
[0056] Next, a principle of nine-viewpoint stereoscopic image
display will be explained by using FIG. 4.
[0057] The cylindrical lens portions 2a constituting a horizontal
lenticular lens 2 are provided corresponding to p(=3) lines of
horizontal pixel lines consecutively arranged in the vertical
direction on the display unit 1. In FIG. 4, only a cylindrical lens
portion 2a corresponding to three horizontal pixel lines is
shown.
[0058] Rays of light from horizontal pixel lines ld1, ld2, and ld3
adjacent to each other in the vertical direction on the display
unit 1 are formed image on horizontal lens lines lm1, lm2, and lm3
which are adjacent to each other in the vertical direction on the
shift lenticular array 3 by the vertical optical power of this
horizontal cylindrical lens 2 (cylindrical lens portion 2a).
[0059] Rays of display light emerged from pixels D1 to D9 of the
horizontal pixel line ld1 are condensed in the horizontal lens line
lm1 on the shift lenticular array 3 by the optical power of the
horizontal lenticular lens 2. Then, the rays of display light are
oriented in the direction of each viewpoint in the horizontal
direction by the optical power of a cylindrical lens portion 31 on
this horizontal lens line lm1, and reach the observation area
4.
[0060] At this time, the rays of display light emerged from the
pixels D1 to D9 reach the viewpoints E1 to E9 in the observation
area 4 respectively. The positional relation among the pixels D1 to
D9, cylindrical lens portion 31, and viewpoints E1 to E9 is the
same as the relation in a nine-viewpoint multiviewpoint
stereoscopic display with general vertical lenticular lenses.
[0061] Viewpoint images that the pixels on the horizontal pixel
line ld2 display are for three (=q) viewpoints as shown in FIGS. 2
and 4. The pixel arrangement order on this horizontal pixel line
ld2 horizontally shifts by three to the pixel arrangement order on
the horizontal pixel line ld1.
[0062] Rays of display light emerged from pixels D1 to D9 of the
horizontal pixel line ld2 are condensed in the horizontal lens line
lm2 on the shift lenticular array 3 by the optical power of the
horizontal lenticular lens 2. Then, the rays of display light are
oriented in the direction of each viewpoint in the horizontal
direction by the optical power of a cylindrical lens portion 32 on
the horizontal lens line lm2, and reach the observation area 4.
[0063] A position of a horizontal center of the cylindrical lens
portion 32 shifts by a predetermined amount, explained later in
detail, to a horizontal center of the cylindrical lens portion 31.
Hence, the rays of display light emerged from the pixels D1 to D9
on the horizontal pixel line ld2 reach viewpoint positions E1 to E9
respectively through the cylindrical lens portion 32, but do not
reach other viewpoint positions.
[0064] Similarly, viewpoint images that the pixels on the
horizontal pixel line ld3 display also are for three (=q)
viewpoints. The pixel arrangement order on this horizontal pixel
line ld3 horizontally shifts by three to the pixel arrangement
order on the horizontal pixel line ld2.
[0065] Rays of display light rays emerged from pixels D1 to D9 of
the horizontal pixel line ld3 are condensed in the horizontal lens
line lm3 on the shift lenticular array 3 by the optical power of
the horizontal lenticular lens 2. Then, the rays of display light
are oriented in the direction of each viewpoint in the horizontal
direction by the optical power of a cylindrical lens portion 33 on
the horizontal lens line lm3, and reach the observation area 4.
[0066] A position of a horizontal center of the cylindrical lens
portion 33 shifts by a predetermined amount to a horizontal center
of the cylindrical lens portion 32. Hence, the rays of display
light emerged from the pixels D1 to D9 on the horizontal pixel line
ld3 reach viewpoint positions E1 to E9 respectively through the
cylindrical lens portion 33.
[0067] FIGS. 5 to 7 show optical actions in the horizontal
direction for stereoscopic image display in this embodiment. FIGS.
5 to 7 show sections respectively by horizontal planes that pass
the horizontal pixel line ld1 and horizontal lens line lm1, the
horizontal pixel line ld2 and horizontal lens line lm2, and the
horizontal pixel lines ld3 and horizontal lens line lm3
respectively in FIGS. 2 to 4.
[0068] This embodiment acts similarly to a usual nine-viewpoint
lenticular type stereoscopic display in each of these sections.
[0069] In FIG. 5, rays of display light emerged from pixels D1 to
D9 in a consecutive pixel area 111 on the display unit 1 reach
viewpoints E1 to E9 (41-1), corresponding respectively, on the
observation area 4 through a cylindrical lens portion 31-1 of the
shift lenticular array 3, but does not reach other
non-corresponding observation positions.
[0070] Similarly, rays of display light emerged from pixels D1 to
D9 in a consecutive pixel area 112 on the display unit 1 reach
viewpoints E1 to E9, corresponding respectively, on the observation
area 4 through a cylindrical lens portion 31-2 of the shift
lenticular array 3, but does not reach other non-corresponding
observation positions.
[0071] Rays of display light that are emerged from each pixel in
the area 111 of the display unit 1 and pass a cylindrical lens
portion except the cylindrical lens portion 31-1 of the shift
lenticular array 3, for instance, a cylindrical lens portion 31-2
and reach viewpoints E1 to E9 in a range different from a range
41-2 on the observation area 4. Here, the arrangement of the
viewpoints E1 to E9 in the range 41-2 is the same as that of
observation positions E1 to E9 in the range 41-1.
[0072] In addition, the rays of display light that are emerged from
each pixel in the area 111 of the display unit 1 and pass a
cylindrical lens portion except the cylindrical lens portions 31-1
and 31-2 reach observation positions E1 to E9, having the same
arrangement, in a range different from the two ranges 41-1 and 41-2
on the observation area 4.
[0073] In this manner, rays of light emerged from the respective
pixels D1 to D9 in the area 111 on the display unit 1 reach
viewpoints E1 to E9 within a range other than the range 41-1 while
reaching viewpoints E1 to E9 within the range 41-1 in the
observation area 4 as described above. Thus, in consequence, a
nine-viewpoint stereoscopic image can be displayed since only the
rays of light from the respective pixels D1 to D9 of the display
unit 1 reach viewpoints E1 to E9 on the observation area 4
respectively and viewpoints E1 to E9 are repeatedly formed on the
observation area 4.
[0074] Similarly, also in the sections that pass the horizontal
pixel lines ld2 and ld3 on the display unit 1, and the horizontal
lens lines lm2 and lm3 on the shift lenticular array 3, which are
shown in FIGS. 6 and 7, the rays of light from the respective
pixels D1 to D9 of the display unit 1 reach only the corresponding
viewpoints E1 to E9 on the observation area 4 respectively.
Similarly to the state in the section explained in FIG. 5,
viewpoints E1 to E9 are formed on the observation area 4
repeatedly, and a nine-viewpoint stereoscopic image can be
displayed.
[0075] FIG. 8 is an explanatory diagram showing the sections shown
in FIGS. 5 to 7 with being stacked, and three types of horizontal
pixel lines ld1, ld2, and ld3 of the display unit 1 are shown with
being mutually shifted horizontally. However, the horizontal
lenticular lens 2 is omitted in FIG. 8.
[0076] Here, relational expressions among horizontal parameters
concerning stereoscopic image display will be explained by using
FIGS. 5 to 8. In addition, the number of viewpoints is defined to
be generalized as r=p.multidot.q in these relational
expressions.
[0077] When a horizontal pixel pitch of the display unit 1 is Hd, a
horizontal pitch between cylindrical lens portions constituting one
horizontal line in the shift lenticular array 3 is Hm, a horizontal
shift amount of positions of a cylindrical lens portion each time a
horizontal line of the shift lenticular lens array is shifted by
one line in the vertical direction is Hm_dis, air conversion
distance between the display unit 1 and shift lenticular lens array
3 is L1, air conversion distance between the shift lenticular lens
array 3 and the observation area 4 is L0, separation width in the
observation area 4 corresponding to pixels D1 to Dr (D9 in the
drawing) is E, each horizontal width of observation positions
(viewpoints) E1 to Er (E9 in the drawing) is He, and a refractive
index and a horizontal curvature radius of the cylindrical lens
portions constituting the shift lenticular array 3 are n and rh
respectively, the following relational expressions stand up by
using fundamental geometrical relations and a lens principle.
1 (r - 1) .multidot. Hd:(r - 1) .multidot. He = L1:L0 (h1) r
.multidot. Hd:Hm = L1 + L0:L0 (h2) He .multidot. (r - 1) = E (h3)
Hm_dis:Hd .multidot. q = L0:L1 + L0 (h4) rh = (1 - n) .multidot. L1
(h5)
[0078] When independent variables are L0, Hd, E, p, q, and r
(=p.multidot.q), solutions of these relational expressions are as
follows:
L1=Hd.multidot.L0.multidot.(r-1)/E
He=E/(r-1)
Hm=r.multidot.Hd.multidot.E/((r-1).multidot.Hd+E)
Hm.sub.--dis=E.multidot.Hd.multidot.q/((r-1).multidot.Hd+E)
rh=(1-n)Hd.multidot.L0.multidot.(r-1)/E
[0079] For example, when Hd=0.3 mm, L0=600 mm, p=3, q=3, r=9, E=200
mm, and n=1.51, then, L1=7.2 mm, He=25 mm, Hm=2.668, Hm_dis=0.889
mm, and rh=3.672 mm.
[0080] Next, the optical action of the horizontal lenticular lens 2
in this embodiment will be explained. This apparatus in this
embodiment leads rays of display light from each horizontal pixel
line of the display unit 1 to a corresponding horizontal lens line
in the shift lenticular array 3, and leads the rays of light from
pixels arranged in a matrix by a cylindrical lens portion whose
arrangement shifts every horizontal lens line of the shift
lenticular array 3 to each viewpoint that is horizontally arranged
in a vertically-striped shape on the observation area 4.
[0081] Hence, when the rays of display light emerged from each
horizontal pixel line leaks into a horizontal lens line on the
shift lenticular array 3 that does not correspond, a crosstalk
arises. The horizontal lenticular lens 2 operates as a member to
suppress this.
[0082] FIG. 9 is a vertical section of the stereoscopic image
display apparatus according to this embodiment. Each of the
cylindrical lens portions that constitutes the horizontal
lenticular lens 2 has an optical power only in the vertical
direction, and does not have an optical power in the horizontal
direction corresponds to a set of three (=p) vertical pixels, and
plays a role of making rays of light from a set of three pixels
forms images on three corresponding horizontal lens lines on the
shift lenticular array 3. Owing to this, the rays of display light
emerged from each horizontal pixel line on the display unit 1 are
led to each corresponding horizontal lens line on the shift
lenticular array 3.
[0083] Rays of light that are emerged from horizontal pixel lines
101 (ld1), 102 (ld2), and 103 (ld3), which are shown in FIG. 9, and
are incident on respective corresponding cylindrical lens portions
201 in the horizontal lenticular lens 2 are formed images on
corresponding horizontal lens lines 301 (lm1), 302 (lm2), and 303
(lm3) on the shift lenticular array 3. Rays of light emerged from
other horizontal pixel lines are also formed images on respective
corresponding horizontal lens lines on the shift lenticular array 3
similarly.
[0084] In addition, when conditions between spaces between the
display unit 1, horizontal lenticular lens 2, and shift lenticular
array 3, which will be explained later, and horizontal pitches of
these three components are satisfied, for example, rays of light
that are emerged from a horizontal pixel line 101' (ld1) and are
incident on a cylindrical lens portion 203, which does not
correspond to the horizontal pixel line 101' originally, in the
horizontal lenticular lens 2 are also condensed on a horizontal
lens line 311 on the shift lenticular array 3 that corresponds to
the horizontal pixel line 101 (ld1) whose pixel arrangement order
is the same as that of the horizontal pixel line 101'. Hence, a
problem does not occur in the stereoscopic image display (for
example, rays of display light emerged from the horizontal pixel
line 101' do not reach viewpoints other than the corresponding
viewpoints by being incident on horizontal lens lines 312, 313, and
the like).
[0085] In addition, it is also possible to use horizontal slits
instead of respective cylindrical lenses constituting the
horizontal lenticular lens 2 so as to limit a range where rays of
light diffuse in the vertical direction. Since structure becomes
simple when the horizontal slits are used, it is possible to
constitute the apparatus at a low price. On the other hand, it is
preferable to use the cylindrical lenses from the viewpoint of
improving a light efficiency.
[0086] Next, relational expressions among vertical parameters
concerning stereoscopic image display will be explained by using
FIG. 9. In addition, the number of viewpoints is generalized as
r=p.multidot.q in these relational expressions.
[0087] When Lv1 is air conversion distance between the display unit
1 and horizontal lenticular lens 2, and Lv2 is air conversion
distance between the horizontal lenticular lens 2 and shift
lenticular array 3, the following relational expressions stand
up:
2 Vd:Vm = Lv1:Lv2 (v1) 2 .multidot. p .multidot. Vm:VL = Lv1 +
Lv2:Lv1 (v2) 1/fv = 1/Lv1 + 1/Lv2 (v3)
[0088] where, Vd is a pitch of the pixels in the vertical direction
on the display unit 1, Vm is a pitch of the cylindrical lens
portions in the vertical direction on the shift lenticular array 3
and fv is a focal length of each cylindrical lens portion,
constituting the horizontal lenticular lens 2, in the vertical
direction.
[0089] Furthermore, as a relational expression that connects a
horizontal parameter, concerning the above-described stereoscopic
image display, with the vertical parameters, the following
expression stands up in regard to positions of the display unit 1
and shift lenticular array 3:
Lv1+Lv2=L1 (hv1)
[0090] In addition, the horizontal lenticular lens 2 is for
preventing display light, emerged from each horizontal pixel line,
from leaking into a horizontal lens line on the shift lenticular
array 3 that does not correspond. Hence, it is also possible to
replace it by a limiting mask etc. which has transmissive portions
and shielding portions, which are long in the horizontal direction,
besides horizontal lenticular lens 2.
[0091] (Embodiment 2)
[0092] Though the display unit 1 is explained as a monochrome
display unit in the above-described Embodiment 1, there is a
possibility of causing so-called color breakup (color separation)
in the observation area 4 when this method is applied to a color
display unit, where R, G, and B are arranged in a vertically
striped manner as it is. The color breakup is a phenomenon that
only the light from a subpixel in a specific color can be observed
but the light from a subpixel in a specific color in a certain
position on the observation area cannot be observed. This is caused
by the relation between positions of subpixels constituting R, G,
and B and positions of cylindrical lens portions of the shift
lenticular array 3.
[0093] When pixels corresponding to r viewpoints are arranged on
horizontal pixel lines of the display unit 1 cyclically as the
above-described Embodiment 1, it is sufficient to perform the
followings so as to suppress color breakup.
[0094] Viewpoints are not assigned by a pixel, but are assigned by
a subpixel including the division of color display.
[0095] The number r of viewpoints is set so as not to be a multiple
of three (at this time, since it is r=p.multidot.q, neither p nor q
are multiples of three).
[0096] When such pixel arrangement is adopted, subpixels on each
horizontal pixel line of the display unit 1 are arranged so that
the relation among viewpoints and colors may go around by
r.multidot.3 pieces of subpixels whose value is the L.C.M. of 3 and
r, and this is repeated thereafter.
[0097] Furthermore, a viewpoint of a subpixel horizontally shifts
by q every pixel row (horizontal pixel line), and since q is not a
multiple of three, subpixels for the same viewpoint that are the
nearest on the display unit have different colors if their rows are
different. Owing to this, the color breakup does not arise.
[0098] When the number of rows of a pixel matrix be p, numbers of
subpixels corresponding to R, G, and B of the same viewpoint
respectively in an expanded matrix which has
3.multidot.p.multidot.r subpixels become equal to each other.
Hence, color breakup does not arise since the numbers of subpixels
of R, G, and B that can be observed in each viewpoint position are
equal.
[0099] FIG. 10(A) is a drawing showing the distribution of
viewpoints to subpixels when p=2, q=4, and r=8. Though this
subpixel arrangement is similar to the arrangement shown in
Embodiment 1 basically and is the same as the case of p=2 and q=4,
this is performed not by a pixel, but by a subpixel of R, G, or B
(in the drawing, subpixels are denoted as r, g, and b).
[0100] In consideration of the relation among R, G, and B and the
relations of viewpoints, it can be seen that a matrix consisting of
eight subpixels of 2.multidot.4 is not a basic matrix in this
subpixel arrangement, but a matrix that consists of subpixels of
48=2.multidot.24 that are enclosed with a frame becomes a basic
matrix to be repeated thereafter.
[0101] In a horizontal line of 48 subpixels of this basic matrix,
there is one subpixel (for example, a pixel D1 of R is one) of each
color in each viewpoint. Hence, two subpixels of each color in each
viewpoint exist in the basic matrix.
[0102] Nevertheless, this arrangement method has a possibility that
color expression of an image becomes unnatural partially since a
basic matrix to the number r of viewpoints becomes excessively
large.
[0103] It is possible to prevent such a problem by adopting the
following structure, and it is also possible to lessen the basic
matrix.
[0104] That is, a linage p of the number of viewpoints
r=p.multidot.q is made an integral multiple of the number of color
divisions, c (in many cases, it is 3 corresponding to R, G, and B),
and, the number of columns, q is made not to be an integral
multiple of the number of color divisions, c.
[0105] The assignment of viewpoints is not performed by a pixel,
but is performed by a subpixel including the division of color
display. Thus, the L.C.M. of the number r of viewpoints and 3 is r,
and a basic matrix becomes p rows.times.r columns.
[0106] FIG. 10(B) is a drawing showing how to display images with
12 viewpoints to respective subpixels when the stereoscopic image
with 12 viewpoints that P=3, q=4, and r=12 is displayed on a color
display unit where subpixels of R, G, and B are arranged in a
vertically striped manner.
[0107] In this embodiment, viewpoints are not assigned by pixel,
but are assigned by subpixel including the division of color
display, and the assignment of viewpoint images to subpixels and
positions of cylindrical lens portions on the shift lenticular
array 3 that correspond to it are similar to those in Embodiment 1
except that the number of viewpoints is made to be
3.multidot.4=12.
[0108] Namely, viewpoint images corresponding to twelve viewpoints
E1 to E12 are repeatedly displayed sequentially by a subpixel in
each horizontal pixel line of the display unit 1. Subpixels are
arranged by being horizontally shifted by four (=q) subpixels with
every horizontal pixel line shift and the subpixel arrangement goes
around by three (=p) rows.
[0109] In addition, each of the cylindrical lens portions
constituting the horizontal lenticular lens 2 corresponds to three
(=p) horizontal pixel lines on the display unit 1, and rays of
light from these three horizontal pixel lines on three
corresponding horizontal lens lines are formed images on the shift
lenticular array 3 by the cylindrical lens portions.
[0110] All the relational expressions shown in the above-described
Embodiment 1 stand up in the case of P=3, q=4, and r=12.
[0111] As shown by subpixels a, b, and c in FIG. 10(B), subpixels
corresponding to the viewpoint E1 are mutually arranged nearly, and
the subpixels a, b, and c display colors of R, G, and B
respectively. It can be seen that the color breakup does not arise
in the observation area 4 by display light from these subpixels
reaching the same viewpoint position E1. This is also similar to
those at other viewpoints.
[0112] Though the number of viewpoints is larger than the case of
p=2, q=4, and r=8 that has been already explained, it is possible
to further excellently suppress the color breakup since the size of
the basic pixel matrix is 3.times.12=36, that is, the pixel matrix
is small.
[0113] (Embodiment 3)
[0114] In each of the above-described Embodiments, since the
horizontal lens lines of the shift lenticular array 3, in which
arrangement patterns of the cylindrical lens portions are different
from each other, are made to correspond to respective horizontal
pixel lines of the display unit 1, it is possible to lead display
light at different viewpoint positions if vertical positions are
different even if horizontal positions of pixels of respective
horizontal pixel lines are the same. Then, in consequence, this
relieves the degradation of resolution in one direction for the
other direction by distributing pixels of the display unit 1 to
respective viewpoints in a matrix-like pattern to distribute the
degradation of resolution, arising in either of the horizontal
direction or the vertical direction, in both directions.
[0115] Hence, it is also possible to perform the distribution of
pixels, explained in Embodiment 1, to respective viewpoints by
other different methods. In this Embodiment and Embodiment 4
described later, the distribution of pixels to respective
viewpoints by methods different from that in Embodiment 1 will be
explained.
[0116] Respects different from Embodiment 1 will be emphatically
explained in this embodiment. Also in this embodiment, a
stereoscopic image display apparatus is constituted by using the
display unit 1, horizontal lenticular lenses 2, and shift
lenticular array 3.
[0117] FIG. 11 shows a distribution method of pixels to respective
viewpoints that is different from that in Embodiment 1 in the case
of p=3, q=3, and r=9.
[0118] In Embodiment 1, viewpoints are shifted by three (=q rows)
pixels every horizontal pixel line as shown in FIG. 2. But, in this
embodiment, two pixels are shifted in between a first horizontal
pixel line and a second horizontal pixel line, four pixels are
shifted in between the second horizontal pixel line and a third
horizontal pixel line, and three pixels are shifted in between the
third horizontal pixel line and the first horizontal pixel line.
Hereafter, this pattern is repeated.
[0119] In this manner, so long as an arrangement pattern of the
cylindrical lens portions on the shift lenticular array 3 is
changed even if pixels are totally shifted by 2+3+4=9 (=r) during 3
(=p) horizontal pixel lines, it is possible to lead rays of display
light, emerged from respective pixels, to respective corresponding
viewpoints.
[0120] FIG. 12 is a drawing showing a cylindrical lens arrangement
pattern of the shift lenticular array 3 in this embodiment. A
horizontal shift amount dis1 between a cylindrical lens portion of
the horizontal lens line lm1 corresponding to the horizontal pixel
line ld1 and a cylindrical lens portion corresponding to the
horizontal pixel line ld2 is shown in dis1=Hm/9.multidot.2. Where
Hm is a horizontal interval between cylindrical lens portions in
one horizontal lens line of the shift lenticular array 3.
[0121] Similarly, a horizontal shift amount dis2 between a
cylindrical lens portion of the horizontal lens line lm2 and a
cylindrical lens portion of the horizontal lens line lm3 is shown
in dis2=Hm/9.multidot.4.
[0122] Furthermore, a horizontal shift amount dis3 between a
cylindrical lens portion of the horizontal lens line lm3 and a
cylindrical lens portion of the horizontal lens line Im1 is shown
in dis3=Hm/9.multidot.3. Hereafter, this pattern is repeated. Here,
9=r=p.multidot.q.
[0123] Since the arrangement of pixels for each viewpoint becomes
asymmetric on the entire display unit 1 when the display unit 1 is
constituted in this manner, there is a possibility of making the
decrease of resolution not further stand out.
[0124] Among relational expressions explained by Embodiment 1, all
the relational expressions other than the relational expression h4
concerning a horizontal shift amount of a cylindrical lens stand up
in this embodiment.
[0125] (Embodiment 4)
[0126] Though viewpoint images corresponding to r (=p.multidot.q)
pieces of viewpoints are displayed by r pieces of pixels lined up
horizontally in the above-described Embodiments 1 to 3, it is also
possible to adopt structure different from these. Respects
different from Embodiments 1 to 3 will be emphatically explained
also in this embodiment.
[0127] Also in this embodiment, a stereoscopic image display
apparatus is constituted by using a display unit 1, horizontal
lenticular lens 2, and shift lenticular array 3.
[0128] Also in this embodiment, rays of light from a set of
horizontal pixel lines (for example, ld1, ld2, and ld3) on the
display unit 1 are formed images on horizontal lens lines (for
example, lm1, lm2, and lm3) on the shift lenticular array 3, which
correspond respectively, by the optical actions of the horizontal
lenticular lens 2.
[0129] FIG. 13 shows a distribution method of pixels to respective
viewpoints that is different from those in Embodiments 1 to 3 in
the case of p=3, q=3, and r=9.
[0130] In this Embodiment, viewpoint images corresponding to
viewpoints E1, E4, and E7 are displayed every three (=P) viewpoints
in pixels D1, D4, and D7 on the horizontal pixel line ld1.
Similarly, on horizontal pixel lines ld2 and ld3, viewpoint images
corresponding to viewpoints E2, E5, and E8, and E3, E6, and E9 are
displayed every three (=p) viewpoints in pixels D2, D5, and D8, and
D3, D6, and D9.
[0131] FIGS. 14 to 16 show horizontal sections including the
horizontal pixel line ld1 and horizontal lens line lm1, the
horizontal pixel line ld2 and horizontal lens line lm2, and the
horizontal pixel lines ld3 and horizontal lens line lm3
respectively in this embodiment. Furthermore, the horizontal
lenticular lens 2 is omitted in these drawings. Hereafter, the
principle of the stereoscopic image display in this embodiment will
be explained by using these drawings.
[0132] In FIG. 14, rays of display light from the pixels D1, D4,
and D7 in a consecutive area 111 on the horizontal pixel line ld1
pass a cylindrical lens portion 31-1 of the shift lenticular array
3, and reach the viewpoints E1, E4, and E7 in a range 41-1,
corresponding respectively, on an observation area 4. As explained
later in detail, by properly choosing an aperture rate kd of pixels
of the display unit 1, rays of display light from the pixels D1,
D4, and D7 cannot reach viewpoints other than the viewpoints E1,
E4, and E7 corresponding on the observation area 4.
[0133] Rays of display light from respective pixels in other areas
on the horizontal pixel line ld1 also pass the cylindrical lens
portions of the shift lenticular array 3, and reach the viewpoints
E1, E4, and E7 corresponding respectively without reaching other
non-corresponding viewpoints.
[0134] As shown in FIGS. 15 and 16, rays of display light from the
pixels D2, D5, and D8, and D3, D6, and D9 corresponding to the
viewpoints E2, E5, and E8, and E3, E6, and E9 on the horizontal
pixel lines ld2 and ld3 reach the viewpoints E2, E5, and E8, and
E3, E6, and E9 respectively by an arrangement pattern of the
cylindrical lens portions on the shift lenticular array 3 where
positions of the cylindrical lens portions on the corresponding
horizontal lens lines lm2 and lm3 of the shift lenticular array 3
shifts horizontally, and do not reach other non-corresponding
viewpoints.
[0135] Further detailed explanation will be performed by using FIG.
14. The center distance between pixels D1 and D7 is 2.multidot.Hd
corresponding to (q-1).multidot.Hd, and hence, separation width in
the observation area 4 owing to it is 6.multidot.He corresponding
to (r-p).multidot.He, where width in the case of regarding each
viewpoint as an area is "He".
[0136] "He" is associated with the separation width E of r
viewpoints by the following relation:
E=(r-1).multidot.He (h100)
[0137] Hence, E=8.multidot.He in the case of the structure in FIG.
14.
[0138] At this time, the following relational expression stands
up:
(q-1).multidot.Hd:(r-p).multidot.He=L1:L0 (h101)
[0139] Hence, a space Hm between cylindrical lens positions of the
shift lenticular array 3 satisfies the following relation:
q.multidot.Hd:Hm=L1+L0:L0 (h102)
[0140] Moreover, the divergence of display light from the pixel D1
in the observation area 4 is given as
Hd.multidot.kd.multidot.L0/L1+Hm, since rays of light that are
emerged from both ends of an effective pixel portion and are
incident on a center of a corresponding cylindrical lens portion in
the shift lenticular array 3 diverge to an amount obtained by
adding divergence width of the rays in the observation area 4, to
the width of the cylindrical lens portion, where kd is an aperture
rate of a pixel. Thus, conditions for rays of display light from
the pixel D1 being accommodated within the width of the viewpoint
(area) E1 not to leak to adjacent viewpoints are as follows:
Hd.multidot.kd.multidot.L0/L1+Hm=He (h103)
[0141] Resolving expression (h103) from expression (h100),
L1=Hd.multidot.L0.multidot.(r-1)/(p.multidot.E)
He=E/(r-1)
Hm=Hd.multidot.E.multidot.r/(Hd.multidot.(r-1)+p.multidot.E)
kd=(E.multidot.p-Hd.multidot.(r-1).multidot.(r-1))/((E.multidot.p+Hd.multi-
dot.(r-1)).multidot.p)
[0142] So long as these expressions are satisfied, rays of display
light from the pixels D1, D4, and D7 in FIG. 14 reach only the
viewpoints E1, E4, and E7 respectively among the viewpoints E1 to
E9 corresponding to nine viewpoints, and do not reach other
non-corresponding viewpoints.
[0143] In addition, similarly also in the sections shown in FIGS.
15 and 16, rays of display light from the pixels D2, D5, and D8,
and the pixels D3, D6, and D9 reach only viewpoints E2, E5, and E8,
and E3, E6, and E9 respectively, which correspond to the
above-described pixels, among nine viewpoints E1 to E9, and do not
reach other non-corresponding viewpoints.
[0144] FIG. 17 is an explanatory diagram showing the sections shown
in FIGS. 14 to 16 with being stacked, and three types of horizontal
pixel lines ld1, ld2, and ld3 of the display unit 1 are shown with
being mutually shifted horizontally. The horizontal lenticular lens
2 is omitted in FIG. 17.
[0145] Furthermore, the shift lenticular array 3 is shown by a mere
straight line with omitting a cylindrical lens portion in FIG.
17.
[0146] A shift amount Hm_dis between positions of the cylindrical
lens portions in between the horizontal lens lines lm1, lm2, and
lm3 in the shift lenticular array 3 will be explained by using FIG.
17.
[0147] In this embodiment, a viewpoint corresponding to each pixel
in the horizontal pixel line ld2 of the display unit 1 shifts by
one viewpoint from a viewpoint corresponding to each pixel, whose
horizontal position is the same as that of each pixel in the
horizontal pixel line ld1.
[0148] Hence, rays of display light emerged from a point of a pixel
in FIG. 17, for example, a point B, reach the viewpoint E1 in the
observation area 4 if it is a pixel on the horizontal pixel line
ld1, or reach the viewpoint E2 if it is a pixel on the horizontal
pixel line ld2. When using primary geometry with paying attention
to these two rays of light, a shift amount Hm_dis between positions
of the cylindrical lens portions in among horizontal lens lines
lm1, lm2, and lm3 in FIG. 18 showing a shift lenticular array
pattern according to this embodiment is given by the following
expression:
Hm.sub.--dls:He=L1+L0:L1 (h104)
[0149] Resolving the above-described expression (h104) from
expressions (h100) and (h103),
Hm.sub.--dls=Hd.multidot.E/(Hd.multidot.(r-1)+p.multidot.E)=Hm/r
[0150] Namely, a cylindrical lens portion of the horizontal lens
line lm2 horizontally shifts by {fraction (1/9)} of the horizontal
width Hm of the cylindrical lens portion to a cylindrical lens
portion of the horizontal lens line lm1. In addition, a cylindrical
lens portion of the horizontal lens line lm3 horizontally shifts by
{fraction (1/9)} of the above-described horizontal width Hm to the
cylindrical lens portion of the horizontal lens line lm2.
[0151] (Embodiment 5)
[0152] FIG. 19 shows the structure of a stereoscopic image display
apparatus that is Embodiment 5 of the present invention. The same
reference characters are assigned in this embodiment to components
common to those in Embodiment 1.
[0153] This embodiment differs from Embodiment 1 at a point of
using a diagonal lenticular array sheet 203, diagonally extending
to the horizontal direction, for horizontal light separation
without using a shift lenticular array. Hereafter, this diagonal
lenticular array sheet 203 will be explained.
[0154] FIG. 20(A) is a front view of the shift lenticular array 3
used in Embodiment 1. In Embodiment 1, the cylindrical lens
portions 3a that are arranged with being divided vertically and
horizontally and constitute the shift lenticular array 3
horizontally orient rays of display light from the display unit 1
to each viewpoint.
[0155] On the other hand, the diagonal lenticular array sheet 203
in which the diagonal cylindrical lens portions 203a corresponding
to lens portions made by diagonally connecting the cylindrical lens
portions 3a in FIG. 20(A) are repeatedly arranged horizontally is
used in this Embodiment as shown in FIG. 20(B).
[0156] Each of the diagonal cylindrical lens portions 203a shown in
FIG. 20(B) has an optical power in the horizontal direction, and
does not have an optical power in the vertical direction. It is
possible to produce such a diagonal cylindrical lens portion 203a
by grinding a die from die material with diagonally moving, for
example, a thin rotating cutting tool in a horizontal plane and
performing plastic molding by using this die.
[0157] FIG. 21 is a schematic diagram for explain a manufacturing
method of a die used for molding. Reference numeral 401 denotes a
die material under processing, reference numeral 402 denotes a
turning tool, and reference numeral 403 denotes a rotation shaft of
the turning tool 402.
[0158] The turning tool 402 rotates in a plane parallel to a
surface 401a of the die material and the rotation shaft 403 of the
turning tool 402 is orthogonal to the surface 401a.
[0159] The length (OB) of the turning tool is made to be equal to a
radius of curvature of the diagonal cylindrical lens portion 203a
in the horizontal direction (a direction in a plane parallel to the
surface 401a). The turning tool 402 is advanced in a direction,
which inclines by a predetermined angle to the direction of the
rotation shaft 403, in a surface 401b of the die material 401 with
rotating in the plane parallel to the surface 401a, and cuts the
die material 401.
[0160] It is possible to form a groove 404, having a curvature in
the horizontal direction (a direction parallel to the surface 401a)
and not having a curvature in the vertical direction (a direction
of the rotation shaft of the turning tool 402), by such a method.
Hence, a die is produced, the die that is for producing the
diagonal lenticular array sheet 203, which has an optical power
only in the horizontal direction but does not have an optical power
in the vertical direction, and in which the diagonal cylindrical
lens portions 203a line up horizontally, as explained in FIG. 20(B)
by repeatedly forming this groove 404.
[0161] The diagonal lenticular array sheet 203 will be explained by
using FIGS. 20(A) and 20(B) again. As already described, the
diagonal cylindrical lens portions 203a shown in FIG. 20(B)
correspond to a member that cylindrical lens portions 3a of the
shift lenticular array 3 shown in FIG. 20(A) are diagonally
connected. For example, a horizontal curvature and a horizontal
pitch of the cylindrical lens portions 203a in a horizontal plane
500 are set equally to a horizontal curvature and a horizontal
pitch of the cylindrical lens portions 3a shown in FIG. 20(A).
[0162] In addition, an inclination angle .theta. of the diagonal
cylindrical lens portion 203a in FIG. 20(B) is given by:
.theta.=tan.sup.-1(Vm/Hm.sub.--dis)
[0163] where Vm is a vertical pitch and Hm_dis is a horizontal
shift amount of the cylindrical lens portions 3a in FIG. 20(A).
[0164] Namely, the diagonal lenticular array sheet 203 has an
optical action, being similar to that of the shift lenticular array
3 according to Embodiment 1, on horizontal lines corresponding to
the horizontal lens lines lm1, lm2, and lm3 in Embodiment 1.
[0165] Hence, it is possible in this embodiment to perform the
distribution of pixels to nine viewpoints similarly to that in
Embodiment 1.
[0166] (Embodiment 6)
[0167] In this embodiment, in particular, structure will be
explained, the structure that one cylindrical lens portion
constituting a horizontal lenticular lens 2 corresponds to one
horizontal pixel line on a display unit 1, and that rays of display
light from one horizontal pixel line are formed images vertically
on one corresponding horizontal lens line in a shift lenticular
array 3.
[0168] In Embodiment 1 and the like, structures are explained, the
structures that the number of viewpoints is r, and the width of one
cylindrical lens portion constituting the horizontal lenticular
lens 2 corresponds to p lines of horizontal pixel lines in the case
of regarding a pixel arrangement matrix, which corresponds to
respective viewpoints that are arranged on the display unit 1, as
r=p (rows).times.q (columns). In this case, rays of display light
from p lines of horizontal pixel lines corresponding to one
cylindrical lens are formed images vertically on p lines of
horizontal lens lines in the shift lenticular array 3,
corresponding respectively, by the cylindrical lens portion.
[0169] On the other hand, structure will be explained in this
embodiment, the structure that one cylindrical lens portion
corresponding to one horizontal pixel line is provided, and rays of
display light from the horizontal pixel line are formed images
vertically on one horizontal lens line on the shift lenticular
array 3.
[0170] FIG. 22 shows the schematic structure of a stereoscopic
image display apparatus according to this embodiment. Similarly to
the stereoscopic image display apparatus shown in FIG. 1, the
stereoscopic image display apparatus according to this embodiment
is also constituted by a display unit 1 in which a predetermined
pixel arrangement pattern is performed, a horizontal lenticular
lens 2 in which a plurality of cylindrical lens portions each of
which corresponds to one horizontal pixel line on the display unit
1 is arranged in the vertical direction, and a shift lenticular
array 3 having an arrangement pattern determined in consideration
of the pixel arrangement pattern on the display unit 1 etc. Here,
this embodiment has a characteristic in the respect that each
cylindrical lens portion constituting the horizontal lenticular
lens 2 is provided independently for each horizontal pixel
line.
[0171] FIG. 23 is a front view showing an example of the
arrangement of pixels displaying images that are displayed in the
display unit 1 used in this embodiment and correspond to respective
viewpoints. In this embodiment, since each cylindrical lens portion
of the horizontal lenticular lens 2 corresponds to one horizontal
pixel line, vertical width of each cylindrical lens portion does
not relate to the number of rows (p) included in each matrix.
Nevertheless, as explained later, in order to prevent images,
corresponding to respective viewpoints, from being mixed, it is
preferable to arrange pixels corresponding to respective viewpoints
in a matrix-like pattern that is determined by the positional
relation among respective components of the stereoscopic image
display apparatus described in this embodiment.
[0172] In FIG. 23, the matrix arrangement regarded as p=2 and q=4
for the number of viewpoints r (=8) is formed. That is, the matrix
arrangement is formed by shifting horizontal positions by four (=q)
pixels every horizontal pixel line and making two (=p) lines of
horizontal pixel lines a vertical unit. In other words, horizontal
pixel lines with the same pixel arrangement every other horizontal
pixel line are repeatedly arranged like ld1 and ld2 in FIG. 23.
[0173] It is preferable that each cylindrical lens portion
constituting the shift lenticular array 3 used for the pixel
arrangement shown in FIG. 23 has an optical power only in a
horizontal direction, and has the height corresponding to each
horizontal pixel line of the display unit 1, and the width equal to
that of eight pixels. In addition, it is preferable that all the
arrangement of pixels corresponding to all cylindrical lens
portions on the shift lenticular array 3 is the same so as to
prevent images corresponding to respective viewpoints from mixing.
Hence, since the horizontal pixel lines ld1 and ld2 on the display
unit 1 are arranged alternately in the vertical direction as shown
in FIG. 23, two types of horizontal lens lines in which the
positions of the cylindrical lens portions are mutually shifted by
a half of the cycle (pitch) thereof, are arranged alternately and
repeatedly in the vertical direction.
[0174] FIG. 24 is a vertical sectional view for explaining the
optical action of the horizontal lenticular lens 2 in this
embodiment. Each of cylindrical lens portions constituting the
horizontal lenticular lens 2 corresponds to one horizontal pixel
line, and rays of light from the horizontal pixel line are formed
images in the vertical direction on one corresponding horizontal
lens line by the cylindrical lens portion.
[0175] In FIG. 24, a horizontal pixel line 121 and a horizontal
lens line 321 of the shift lenticular array 3 corresponds to a
cylindrical lens portion 221 constituting the horizontal lenticular
lens 2, and the cylindrical lens portion 221 makes rays of light
from the horizontal pixel line 121 form images in the vertical
direction on the horizontal lens line 321 of the shift lenticular
array 3.
[0176] In FIG. 24, horizontal pixel lines having the same pixel
arrangement pattern on the display unit 1 and a horizontal lens
line having the same lens arrangement pattern are arranged every
other line respectively, and similarly to the relation explained in
Embodiment 1, they are arranged with associating a ratio of
distance (Lv1) between a plane where pixels are arranged on the
display unit 1 and the horizontal lenticular lens 2, and distance
(Lv2) between the horizontal lenticular lens 2 and shift lenticular
lens 3, with a ratio of the width of the horizontal pixel line Vd
to that Vm of the horizontal lens line. Therefore, rays of light
emerged from the horizontal pixel line 121 and incident on a
cylindrical lens portion 222, which does not correspond originally
to the horizontal pixel line 121 are formed images in the vertical
direction on the horizontal lens line 323 in the shift lenticular
array 3 by an optical action of the cylindrical lens portion
222.
[0177] In consequence, since the horizontal lens line 323 has the
lens arrangement pattern of lm1, the rays of light emerge d from
the horizontal pixel line 121 and incident on both cylindrical lens
portions 221 and 222 are incident on the horizontal lens line lm1
in the shift lenticular array 3 that correspond to the horizontal
pixel line ld1 to reach predetermined viewpoints.
[0178] Similarly, even if rays of light from respective horizontal
pixel lines are incident on any cylindrical lens portions
constituting the horizontal lenticular lens 2, the rays of light
are formed images in the vertical direction on the horizontal lens
lines (lm1 and lm2) in the shift lenticular array 3 that correspond
to the arrangement patterns of viewpoint images in the horizontal
pixel lines (ld1 and ld2). Hence, the stereoscopic image display is
normally performed without mutually mixing viewpoint images.
[0179] As above described, it is possible to accurately perform the
association of optical paths from the respective horizontal pixel
lines of the display unit 1 to the corresponding horizontal lens
lines of the shift lenticular array 3 by making each cylindrical
lens portion, constituting the horizontal lenticular lens 3,
correspond to one horizontal pixel line. Hence, it becomes possible
to effectively prevent the mixing of viewpoint images, and it is
possible to reduce color separation generated when color display is
performed.
[0180] (Embodiment 7)
[0181] In each of other embodiments described above, the horizontal
lenticular lens 2 is placed in front of the display unit 1. But, in
this embodiment, structure will be described, the structure in
which the horizontal lenticular lens 2 is arranged between a
display unit 1 that is a transmissive LCD or the like, and a light
source panel that illuminates the display unit 1 from the back side
thereof.
[0182] FIG. 25 is a perspective view showing the structure of a
stereoscopic image display apparatus that is Embodiment 7 of the
present invention. In this embodiment, a transmissive LCD is used
as the display unit 1, and the light source panel 5 is arranged in
the rear of the LCD. In addition, the horizontal lenticular lens 2
is arranged between the display unit 1 and light source panel 5,
and the shift lenticular array 3 is arranged in front of the
display unit 1.
[0183] FIG. 26 is a vertical section of the apparatus according to
this embodiment. FIG. 26 shows the relation among respective
components in the case that pixels in the display unit 1 are
arranged so that three horizontal pixel lines (p=3) makes one
cycle. As shown in FIG. 26, the display unit 1 is arranged
adjacently to the shift lenticular array 3. In addition, each of
the cylindrical lens portions constituting the horizontal
lenticular lens 2 is constituted so as to make illumination light
from the light source panel 5 transmit a corresponding horizontal
pixel line on the display unit 1, and substantially are formed
images on each horizontal lens line of the shift lenticular array
3.
[0184] Such structure makes it possible that rays of display light
from each horizontal pixel line on the display unit 1 are incident
on one horizontal line of the shift lenticular array 3
corresponding to the horizontal pixel line even if a transmissive
LCD is used as the display unit 1, and rays of light from a pixel
corresponding to each viewpoint on the display unit 1 are led to a
corresponding viewpoint similarly to Embodiment 1.
[0185] In the structure of this embodiment, there is a possibility
that the illumination light from the light source panel 5
illuminates upper and lower horizontal pixel lines as well as a
corresponding horizontal pixel line, depending on design conditions
such as a space between the light source panel 5 and display unit
1, and a space between the display unit 1 and shift lenticular
array 3. Since crosstalk in the vertical direction arises when
illumination light from the light source panel 5 illuminates a
horizontal pixel line, which does not correspond originally, in
this manner, excellent stereoscopic vision becomes difficult.
[0186] In order to prevent such crosstalk, it is effective to make
the light source panel 5 have light source lines extending in the
horizontal direction and corresponding to respective horizontal
pixel lines of the display unit 1, or to narrow an effective
aperture of each cylindrical lens portion constituting the
horizontal cylindrical lens 2 and fill other portions with
light-shielding members. FIG. 26 shows the case of using the light
source panel 5 that has light source lines extending horizontally
and corresponding to respective horizontal pixel lines of the
display unit 1, and the horizontal cylindrical lens 2 that has
light-shielding members 2s between cylindrical lens portions.
[0187] In the structure of this embodiment, since the horizontal
lenticular lens 2 is not arranged between the display unit 1 and
shift lenticular lens 3 in comparison with the structure of
Embodiment 1, it is possible to narrow the space L1 between the
display 1 and shift lenticular lens 3. In addition, as it is
obvious from the relational expression (h1) described in Embodiment
1, there is the relation of Hd:He=L1:L0, where horizontal pixel
width is Hd, observation width of each viewpoint (an observation
area 4) is He, and observation distance is L0. Therefore, when
observation is performed at the observation distance L0 by using a
display unit with predetermined horizontal pixel width Hd, it is
possible to narrow the space L1 between the display unit 1 and
shift lenticular lens 3, and hence, it is possible to widen the
width He of each viewpoint.
[0188] FIG. 27 shows the arrangement of pixels corresponding to
respective viewpoints on the display unit 1 used in this
embodiment. FIG. 27 shows the pixel arrangement corresponding to
nine viewpoints (=3.times.3) similarly to Embodiment 1 as an
example of pixel arrangement. Since the horizontal lenticular lens
2 is not arranged between the display unit 1 and shift lenticular
lens 3 in this Embodiment differently from Embodiment 1, it does
not arise to vertically exchange positions between a horizontal
pixel line on the display unit 1 corresponding to each of
lenticular lens portions constituting the horizontal lenticular
lens 2, and a horizontal pixel line that an observer observes.
Therefore, pixel arrangement on the display unit 1 used in this
embodiment differs from the arrangement shown in FIG. 2 showing
Embodiment 1 to become arrangement shown in FIG. 27.
[0189] As above explained, according to each of the above-described
embodiments, it is possible to freely select an image display unit.
In addition, it is possible to provide a multiviewpoint
stereoscopic image display apparatus, in which crosstalk hardly
arises even if a transmissive image display unit with strong
scattering is used, and whose light efficiency is high.
[0190] Furthermore, it is possible to suppress color separation
when performing color display by constituting an image display unit
of c types of pixels that emerge c colors of light that is
different mutually and making p an integral multiple of c without
making q an integral multiple of c.
[0191] Moreover, since the shift lenticular array 3 and diagonal
lenticular array sheet 203 are used for light separation in the
horizontal direction in the above-described embodiments, there are
no mask etc. that shield the light emerged from the display unit 1.
Therefore, light efficiency is higher than that of a conventional
stereoscopic image display apparatus that uses a mask. Hence, it is
possible to display a stereoscopic image that is bright in high
resolution, and can be observed from multiple viewpoints.
[0192] In addition, though the cases of using the shift lenticular
array 3 and diagonal lenticular array sheet 203 for the light
separation in the horizontal direction are described in the
above-described embodiments, it is also good to use an optical
element having optical acting portions whose optical action is
equal to a lens owing to the structure of diffractive gratings as a
lenticular array in present invention.
[0193] Furthermore, though the case that the horizontal lenticular
lens 2 as a limiting member and the shift lenticular array 3 (or,
diagonal lenticular array sheet 203) as a lenticular array are
separated in each of the above-described embodiments, these can be
integrated when both are adjacently arranged. For example, it is
also good to perform integration by joining an optical member
(limiting member), formed by making lens surfaces having optical
actions equal to the horizontal lenticular lens 2 facing a display
unit side, with the shift lenticular array 3 in each of the
above-described embodiments. Alternatively, it is also good to
produce an integrally produced member by forming lens surfaces
having optical actions equal to the horizontal lenticular lens 2,
in a display unit side and a plurality of lens portions of the
shift lenticular array 3 in each of the above-described
embodiments, in an observation area side. Though it is required in
the present invention to align pixels of an image display unit, a
liming member, and a lenticular array in high accuracy, it is
possible to easily align them by integrating the limiting member
and lenticular array as above described.
[0194] In addition, it is possible to also apply this to a
stereoscopic image display apparatus with the number of viewpoints
other than the numbers of viewpoints explained in the
above-described respective embodiments. For example, though it is
desirable to have the number of viewpoints that is four or more, it
is possible to also apply this to those with the numbers of
viewpoints that are two and three.
[0195] While preferred embodiments have been described, it is to be
understood that modification and variation of the present invention
may be made without departing from the sprit or scope of the
following claims.
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